1. Field of the Invention
The present invention relates to a high frequency switch (RF switch) for switching between high frequency signals, and more particularly to a high frequency switch suitable for use as an antenna switch connected to an antenna, e.g., a TDD (Time Division Duplex) switch or the like.
2. Description of the Related Art
Conventional high frequency switches such as antenna switches include a microwave switch disclosed in Patent Document 1 and a transmission and reception switching device disclosed in Patent Document 2, for example.
The microwave switch disclosed in Patent Document 1 has PIN diodes inserted in series and parallel in a signal line. Forward currents are passed through the PIN diodes to turn them on, and the PIN diodes are reversely biased to turn them off, thereby switching between high frequency signals.
The transmission and reception switching device disclosed in Patent Document 2 employs a circuit scheme wherein a switch is constructed of transmission lines and PIN diodes or the like which are connected in series to the transmission lines, the transmission lines and the PIN diodes being connected parallel to a signal transmission line.
There is also known an example wherein a choke coil is connected for the purpose of disconnecting bias circuits for PIN diodes at high frequencies when the PIN diodes are turned off (see Patent Document 3, for example).
Patent Document 1: Japanese Patent No. 2532122
Patent Document 2: Japanese Patent No. 2830319
Patent Document 3: Japanese Patent Publication No. 01-033961